This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-331124, filed Oct. 30, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a suspension for disc drive incorporated in an information processing apparatus, such as a personal computer.
A hard disc drive (HDD) for recording in and reading information from a rotating magnetic disc or magneto-optical disc includes a carriage that can turn around a shaft. The carriage is rotated around the shaft by means of a positioning motor. The carriage is provided with an arm (actuator arm), a suspension mounted on the distal end portion of the arm, a head portion including a slider mounted on the suspension, etc. When the disc rotates at high speed, the slider slightly lifts off the disc surface, whereupon an air bearing is formed between the disc and the slider. The suspension comprises a base portion including a base plate, a beam portion formed of a precision plate spring, a flexure fixed to the beam portion by laser welding or the like, etc. The base plate is fixed to a suspension mounting surface of the arm.
With the advance of compaction of information recorded in the disc and speed-up of the disc drive operation, the disc drive of this type has been required a shorter seek time. In order to shorten the seek time, the disc rotation must be speeded up.
In order to improve the required properties of the suspension, the inventor hereof has proposed a novel suspension in which a base portion and a beam portion are connected by means of a hinge member. According to this prior art, the base portion, beam portion, and hinge member are separate components, so that materials and plate thicknesses corresponding to their respective required properties can be selected individually.
According to a proposal, for example, the spring constant of the hinge member is lowered by making the hinge member thinner than the beam portion. In this case, however, the stiffness of a region of the beam portion near the hinge member is much higher than that of the hinge member. If the disc drive is shocked, therefore, it cannot effectively absorb the shock, so that the slider is brought too heavily into contact with the disc surface. Thus, the shock resistance is a critical problem. In order to enhance the shock resistance, therefore, a proposal is made to form a through hole in the region of the beam portion near the hinge member, thereby lowering the stiffness of that region.
If the through hole is formed in the region of the beam portion near the hinge member, however, the beam portion is caused to flutter by the influence (windage or air turbulence) of air over the disc surface upon the through hole, especially in the case of a disc drive in which the disc rotates at high speed.
Accordingly, the object of the present invention is to provide a suspension that enjoys high shock resistance and is not liable to flutter.
In order to achieve the above object, a suspension in a first aspect of the present invention comprises a base portion, a beam portion with a flexure, a hinge member connecting the base portion and the beam portion to each other, a hole in the beam portion, and a cover portion covering the opening of the hole. According to this invention, there may be provided a suspension that enjoys high shock resistance, and in which the beam portion is light in weight and the incidence of flutter can be restrained.
In order to achieve the above object, a suspension in a second aspect of the invention comprises a base portion, a beam portion with a flexure, a hinge member connecting the base portion and the beam portion to each other, a hole formed in a region of the beam portion near the hinge member so that the stiffness of the region near the hinge member is lowered, and a cover portion covering the opening of the hole. According to this invention, there may be provided a suspension that enjoys higher shock resistance, and in which the beam portion is light in weight and the incidence of flutter can be restrained.
The hinge member is lower in bending stiffness than the base portion and the beam portion. When a bending load is applied to the beam portion, therefore, the hinge member bends, thereby displaying a given spring characteristic. The xe2x80x9chole formed near the hinge memberxe2x80x9d described herein is a hole that is formed in a position nearer to the hinge member than a point halfway between the proximal end (end near the hinge member) of the beam portion and the slider is. Preferably, the hole should be formed so that the center of gravity of the combination of the beam portion and the hinge member is situated nearer to the slider than the hole is.
In each of the suspensions in the first and second aspects, the cover portion may be composed of an unetched portion of the hole of the beam portion formed by partial etching. According to this invention, the cover portion can be constructed using a part of the beam portion, so that the number of components never increases. Besides, the cover portion can be easily formed by utilizing partial etching.
Alternatively, the cover portion may be composed of an extension formed by extending a part of the hinge member toward the beam portion. According to this invention, the cover portion can be constructed using a part of the hinge member, so that the number of components never increases. The cover portion may be composed of a laminar member attached to the beam portion. According to this invention, the cover portion can be easily constructed by attaching a laminar member, such as a tape or foil, to the beam portion.
Furthermore, the cover portion may be composed of a part of the flexure. According to this invention, the cover portion can be constructed using a part of the flexure that is thinner than the hinge member, so that the number of components never increases. The influence of air turbulence can be restrained by closing the opening of the hole by means of the cover portion.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.